Yet in the trade talks currently being held in Auckland, the government has embarked on a "Trust us, we know what we're doing" exercise of huge proportions.

The Trans Pacific Partnership (TPP) is a deal being negotiated between New Zealand and several Asian-Pacific countries (including the United States, Canada and Mexico) that could have sweeping consequences for New Zealand.

Our standards of bio-security, the way Pharmac buys cheap medicines, our ability to parallel import goods from overseas and our government's ability to pass laws to protect public health and the environment (without getting sued by foreign investors if they lose money as a result ) are merely some of the items on the table.

Not that the details will be in the news.

The TPP negotiations are being held under strict secrecy - so much so that the relevant papers are supposed to stay confidential for four years after the deal is finalised.

Under such conditions, Parliament will hardly be able to hold an informed debate about the contents of the TPP.

Parliament's only role afterwards will be in changing New Zealand's existing laws, rights and regulations to make them comply with the provisions of the TPP.

Thankfully, since the United States Congress will need to ratify the final agreement, New Zealanders will probably be able to rely on the transparency of the American system to inform them about what our government has agreed to, and why.

The response so far by Prime Minister John Key to the risks revealed in leaked TPP draft documents has been to issue reassurances along the lines of: "No worries, we won't sign up to those sort of provisions."

Or, as Trade Minister Tim Groser said in June: "The New Zealand Government will not sign any agreement that stops us now, or any government in future, from regulating for public health or any other legitimate policy purposes. We will protect New Zealand's legitimate rights to regulate."

Unfortunately, the repetition of the weasel word "legitimate" renders Groser's assurance almost meaningless.

Ultimately, if foreign investors ever used the TPP agreement to take New Zealand to court, it would be overseas arbitration panels, and not the New Zealand government, that would be deciding what it is "legitimate", and what isn't.

When faced with the possible downsides of the TPP, Key and Groser seem to be claiming that New Zealand can make major gains, but without us needing to make any particularly painful concessions along the way. Good luck with that.

There's an obvious political motive in making reassuring noises at this stage.

However, the danger remains that our negotiators will give ground on intellectual property, copyright, patenting and the purchasing process for generic medicines, while exposing New Zealand to being sued in so-called investor/state disputes.

This will be done in the hope of winning gains on foreign agricultural market access that - at best - appear likely to be phased in only over a 15 or 20-year period.

Democracy loves sunlight.

If New Zealand truly has ruled certain things off the table -as the Americans have openly done - then the government should be saying just what our "no go area" list of TPP exclusions are. Revealing that list would be the best form of reassurance.